Valve apparatus for hydraulic presses.



Patented 001.2, I900.

No. 658,9l5.

J. JAGOBSEN. VALVE APPARATUS FOR HYDRAULIC PRESSES.

(Application filed Apr. 12, 1900.)

(No Model.)

JOHANNES JACOBSEN, OF FRIEDENAU, GERMANY.

VALVE APPARATUS FOR HYDRAULIC PRESSES.

SPECIFICATION forming part of Letters Patent No. 658.915,

dated ember 2,1900.

Application filed April 12, 1900. Serial No. 12,604. (No model.)

To all whom it may concern.-

Be it known that I, J OHANNES Jacossnn, engineer,a subject of the German Em peror,residing at Haufistrasse 8, Friedenau, near Berlin, Germany, have invented a certain new and useful Valve Apparatus for-Hydraulic Presses; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to whichit appertains to make and use the same.

This invention relates to valve apparatus for controlling the action of a hydraulic press with two cylinders which receive pressure fluid alternately from a force-pump.

The invention consists, mainly,in thata piston which controls the supply and discharge of the pressure fluidto and from the press is:

made to work'with such frictional resistance in its casing that the pressure fluid admitted.

behind it effects the reversal of its position as soon as the pressure of the fluid is suflicient to overcome the frictional resistance of the controlling-piston.

An arrangement of valve apparatus operating according to this invention is shown in longitudinal section on the accompanying drawing.

The pressure fiuid enters the apparatus through the supply-port a in order to pass alternately through feed-ports b and 0 into the one or the other presscylinder. The pipes d and e are exhaust-ports which serve to lead off the discharge fluid from the cylinders. In the casing there is contained in a cylindrical bore f a piston g, which has two closely-fitting ends it and 'i. From the feedports -b and c pipes Ia and 1 lead to the two ends of the casing behind the annular shoulders m and n ofthe piston g, In the position of the piston shown the pressure fluid passes from a through the space fand the feed-port b to the one press-cylinder, while the spent fluid passes away from the other cylinder through ports. c'and e. From the feed-port b part of the pressure fluid passes through the pipe k, behind the shoulder m of I piston g. The pressure fluid at the same time is subjected to a gradually-increasing pressure in proportion to the increasing resistanceof the hydraulic press, and when this pressure has thus risenbehind m to such an extent as to overcomethe frictional resistance of the parts it and i of piston; ghis Y will be thereby forced over to the right and the supply-port awill now communicate with the feedaport c and feed-port b with the exhaust-port d. The pressure fluid willtherefore now pass through a into the other presscylinder'. f;

The pressu 'e. behind thecollars m and n can operatefi'n the above-described manner, because theipressure transmitted from a to b or c operatesiu the space f equally in both. directions on, the piston 9, so that such action on g is balanced.

In the position shown the tight fit of the.

piston g is insured by'the cup-leathers o and p and in the opposite position by the cupleathers q and r.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, resents thht"whaI'claim"is'- 1. In a valve mechanism for hydraulic presses, the combination with a casing, of a piston moving in said casing with friction, a supply-port leading to .the casing, feed-ports leading from the casing, exhaust-portsleading from the casing, and passages leading from said feed-portsto the outer ends of the casing to supply pressure to the ends of said piston.

2. In a valve mechanism for hydraulic presses, the combination with a casing, of a supply-port leading-to saidcasiug, feed-ports leading from said casing, exhaust-ports leading from said casing, a piston moving in said casing with friction and acting as a valve to place each of said feed-ports alternately in connection with the supply-port and one of the exhaust-ports, and passages leading from said feed-portsto the ends of the casing to supply pressure to the ends of said piston.

3. In a valve mechanism for hydraulic presses, the combination with acasing, of a piston having the same area at both ends and sliding in said casing with friction, a supplyport leading to the casing, feed-ports leading from the casing, exhaust-ports leading from the casing, and passages leading from said feed-ports to the outer ends of the casing to supply pressure to the ends of the piston.

= In witness whereof I have hereunto set my 'hand in presenceof two witnesses.

J OBANNES JACOBSEN.

Witnesses:

. HENRY Basra-a,-

Womnnaa Ha'urr. 

